Apparatus and method for forming a bending crease in corrugated paperboard

ABSTRACT

An apparatus for forming a bending crease in corrugated paperboard includes a circumferential portion of a wheel. The circumferential portion has a width and a peripheral surface positioned to compressively rollably receive a corrugated paperboard between the surface of the wheel and a support surface. The circumferential portion includes a protrusion extending radially outward from the circumferential portion greater than 0.070 inch. The protrusion extends radially outward from a base to a tip opposite the peripheral surface, the tip having a width less than the width of the base. The protrusion is configured to form a crease in the corrugated paperboard, the crease having sufficient depth and a width less than or equal to the width of the base, thereby resulting in a bend line formed in the corrugated paperboard that is substantially coincident with the formed crease.

FIELD OF THE INVENTION

The present invention relates to apparatus associated with manufacturing paperboard and articles therefrom, and more specifically, to apparatus associated with manufacturing corrugated paperboard and articles therefrom.

BACKGROUND OF THE INVENTION

Corrugated paperboard is commonly used, such as in the manufacture of regular slotted containers (RSCs) that are conventionally provided for shipping of product in a retail environment to prospective customers. Corrugated paperboard is typically manufactured on large high-precision machinery lines called corrugators. Creasing or scoring and cutting of RSC blanks can occur in-line with the corrugator or can be sent to separate manufacturing areas or facilities. Creasing or scoring is performed to provide controlled bending of the corrugated paperboard, and it is extremely important that the ensuing bends substantially coincide with the creases for the RSC to be usable and function as intended.

The achievement of forming acceptable bends in corrugated paperboard during their manufacture continue to present challenges. For example, conventional apparatus often referred to as creasers consist of a rotating wheel 10 (FIG. 1) having a width 22 and scoring profile taken along line of sight 2-2 of FIG. 1, such as shown in FIG. 2. FIG. 2 shows a conventional rectangular protrusion 12 extending radially outwardly from a shoulder 16, terminating at a tip 14 having a height 18 of 0.070 inches. The squared tip 14 is brought into compressive contact with the linerboard to form the crease or score in the corrugated paperboard, the linerboard being the flat sheets that comprise the outer surfaces of a sheet of corrugated paperboard that surround and are bonded to the corrugated or fluted paperboard. While the height 18 of tip 14 is limited to avoid tearing of the linerboard brought into contact with the tip 14, formed creases of insufficient depth in the corrugated paperboard are more likely to produce unacceptable bends in the corrugated paperboard, resulting in the scrapping of the manufactured RSC.

However, increasing the depth of the crease formed in the corrugated paperboard, especially when working with double wall corrugated paperboard (FIG. 3) creates other challenges. As further shown in FIG. 3, increasing the crease depth to an extent greater than the height 18 of tip 14, shoulder 16 of the creaser wheel 10 forms a crushed region 26 in the corrugated paperboard 20, the crushed region 26 having a depth 24 and a width 22 that is much wider than the width of the crease formed by tip 14. As a result of the widened crushed region 26, despite the increased crease depth formed in corrugated paperboard 20, which is the sum of height 18 and depth 24, the formed bend associated with this crease is much more likely to be unacceptable, as the formed bend is much more likely to deviate from the desired bend line defined by tip 14.

An apparatus and method for forming creases in corrugated paperboard that provides an improvement in the number of acceptable bends and thereby reducing scrapping is desirable in the art.

SUMMARY OF THE INVENTION

In an exemplary embodiment, an apparatus for forming a bending crease in corrugated paperboard includes a circumferential portion of a wheel. The circumferential portion has a width and a peripheral surface positioned to compressively rollably receive a corrugated paperboard between the surface of the wheel and a support surface. The circumferential portion includes a protrusion extending radially outward from the circumferential portion greater than 0.070 inch. The protrusion extends radially outward from a base to a tip opposite the peripheral surface, the tip having a width less than the width of the base. The protrusion is configured to form a crease in the corrugated paperboard, the crease having sufficient depth and a width less than or equal to the width of the base, thereby resulting in a bend line formed in the corrugated paperboard that is substantially coincident with the formed crease.

In another exemplary embodiment, a system for forming a bending crease in corrugated paperboard includes a wheel having a circumferential portion. The circumferential portion has a width and a peripheral surface positioned to compressively rollably receive a corrugated paperboard between the surface of the wheel and a support surface. The circumferential portion includes a protrusion extending radially outward from the circumferential portion greater than 0.070 inch. At least a portion of the tip the protrusion has a width less than the width of the circumferential portion. The protrusion is configured to form a crease in the segment of corrugated paperboard. The crease has sufficient depth and a width less than the width of the circumferential portion, thereby resulting in a bend line formed in the segment of corrugated paperboard that is substantially coincident with the formed crease.

In another exemplary embodiment, a method for forming a bending crease in corrugated paperboard includes providing a wheel having a circumferential portion. The circumferential portion has a width and a peripheral surface positioned to compressively rollably receive a corrugated paperboard between the surface of the wheel and a support surface. The circumferential portion includes a protrusion extending radially outward from the circumferential portion greater than 0.070 inch. At least a portion of the tip the protrusion has a width less than the width of the circumferential portion. The protrusion is configured to form a crease in the segment of corrugated paperboard. The crease has sufficient depth and a width less than the width of the circumferential portion, thereby resulting in a bend line formed in the segment of corrugated paperboard that is substantially coincident with the formed crease. The method further includes directing the corrugated paperboard between the protrusion and the support surface to form the crease.

Other features and advantages of the present invention will be apparent from the following more detailed description of the preferred embodiment, taken in conjunction with the accompanying drawings which illustrate, by way of example, the principles of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a known creaser wheel.

FIG. 2 shows a partial side profile view of the known creaser wheel taken along line 2-2 of FIG. 1.

FIG. 3 shows the known creaser wheel of FIG. 1 forming a crease in a corrugated paperboard.

FIG. 4 shows an exemplary embodiment of an apparatus for forming a bending crease in corrugated paperboard.

FIG. 5 shows a partial side profile view of the apparatus taken along line 5-5 of FIG. 4.

FIG. 6 shows a partial side profile view of the apparatus taken along line 6-6 of FIG. 4.

FIG. 7 shows a diagrammatic view of an apparatus and a method for forming a bending crease in corrugated paperboard.

FIG. 8 shows an enlarged front view of apparatus and method for forming a bending crease in corrugated paperboard.

FIG. 9 shows an enlarged front view of apparatus and method for forming a bending crease in corrugated paperboard.

FIG. 10 shows a partial side profile view of an exemplary embodiment of the apparatus.

FIG. 11 shows a partial side profile view of an exemplary embodiment of the apparatus.

Wherever possible, the same reference numbers will be used throughout the drawings to represent the same parts.

DETAILED DESCRIPTION OF THE INVENTION

Provided is an apparatus and method for forming a bending crease in corrugated paperboard, resulting in a bend line formed in the corrugated paperboard that is substantially coincident with the formed crease. In other words, by virtue of the apparatus/method for forming a bending crease in corrugated paperboard, the number of acceptable bends formed in corrugated paperboard articles is increased, resulting in a reduction of scrapped articles.

European Publication EP 1,110,709, which discloses well known problems associated with unacceptable bends formed in corrugated paperboard boxes, is incorporated herein by reference.

As used herein, paperboard is a paper-based material that can be used in packaging as it can be easily cut and formed, and is lightweight and strong. Paperboard is formed of fibrous materials such as wood or other fiber such as sugarcane, bagasse, straw, hemp, cotton, flax, kenaf, abaca and other plant or synthetic sources.

As shown in FIGS. 4 and 5, an apparatus 110 comprises a circumferential portion 28 having an inner facing surface 32 corresponding to an outer facing surface 34 of a wheel 30. In one embodiment, inner facing surface 32 of circumferential portion 28 and outer facing surface 34 of the wheel 30 are secured to each other, such as by press fit, adhesive, weld, chemical surface treatment, one or more fasteners (not shown) extending from one or both of surfaces 32, 34 or other suitable technique. In one embodiment, circumferential portion 28 and wheel 30 are of unitary or one-piece construction As further shown in FIG. 4, wheel 30 includes a center of rotation 31 for rollably securing wheel 30 and circumferential portion 28 such as shown in FIG. 8.

As further shown in FIGS. 4 and 6, circumferential portion 28 includes circumferential segments 36, 38 having corresponding mating features 40. That is, circumferential segment 36 includes notched surfaces 42, 46 that mate with corresponding notched surfaces 44, 48 of circumferential segment 38. As shown in FIG. 4, each set of mating features 40 forms a dovetail joint. In other embodiments, other arrangements of mating features 40 may be used. In one embodiment such as shown in FIG. 4, circumferential segments 36, 38 are substantially identical to each other.

As further shown in FIGS. 4 and 6, circumferential portion 28 can include inner facing surface 32 as well as an adjacent surface 52, with wheel 30 including corresponding outer facing surface 34 and surface 54. That is, when assembled together, inner facing surface 32 of circumferential portion 28 is brought into abutting contact with outer facing surface 34 of wheel 30, and surface 52 of circumferential portion 28 is brought into abutting contact with surface 54 of wheel 30. As further shown in FIG. 6, which is a cross section taken along line 6-6 of FIG. 4, circumferential portion 28 can be secured to wheel 30 upon alignment of respective portions of opening 50 collectively formed in each of circumferential portion 28 and wheel 30 and insertion therein of a fastener 56 such as a screw or other suitable fastener. Although other arrangements may be used, different circumferential portions 28 can be easily installed and removed from wheel 30, or alternately, wheels 30 having different circumferential portions 28 can also be easily installed and removed, such as to accommodate different numbers of layers and/or thicknesses of corrugated paperboard.

As shown in FIGS. 4 and 5, circumferential portion 28 includes a protrusion 58 extending radially outward from circumferential portion 28 to a tip 60. In one embodiment, at least a portion of the profile of tip 60 includes a curve. In one embodiment the curve includes a radius.

As shown in FIG. 5, which is not to scale in order to more clearly show and describe features of the present disclosure, tip 60 of protrusion 58 includes a radius 62 and a length 72 measured from tip 60 to a base 66 of protrusion 58. In one embodiment, tip 60 includes a plurality of perforating features 74, permitting protrusion 58 to form perforated creases, if desired. Base 66 has a width 68, which width 68 is measured from a point of tangency between the outer surface of protrusion 58 and opposed shoulders 64 of circumferential portion 28. As further shown in FIG. 5, opposed shoulders 64 are not parallel to one another, nor are shoulders 64 perpendicular to the outer surface of protrusion 58. As yet further shown in FIG. 5, shoulders 64 form an obtuse angle 76 subtended between the surfaces of shoulder 64 and corresponding surfaces of protrusion 58, permitting a reduced crushed region of corrugated paperboard (as compared to crushed region 26 of FIG. 3) in instances in which the depth of a crease formed in corrugated paperboard is greater than length 72 of protrusion 58. In other embodiments, opposed shoulders 64 can be parallel to one another and/or perpendicular to the outer surface of protrusion 58. As shown in FIG. 5, protrusion 58 includes a taper 75 between base 66 and tip 60. That is, tip 60 has a width less than width 68 of base 66. In one embodiment, such as shown in FIG. 5 the taper 75 extends substantially linearly between base 66 and tip 60. In another embodiment, the taper 75 can extend nonlinearly between base 66 and tip 60. In one embodiment, at least a portion of a profile of tip 60 includes a curve, and in another embodiment, the curve includes a radius. In one embodiment, radius 62 is between about 0.02 inch and about 0.75 inch, between about 0.03 inch and about 0.50 inch, between about 0.04 inch and about 0.35 inch, between about 0.05 inch and about 0.25 inch, between about 0.06 inch and about 0.15 inch, between about 0.07 inch and about 0.10 inch, between about 0.02 inch and about 0.15 inch, between about 0.02 inch and about 0.10 inch, between about 0.02 inch and about 0.08 inch, between about 0.03 inch and about 0.07 inch, between about 0.04 inch and about 0.06 inch, or any suitable sub-range thereof In another embodiment, radius 62 is about 0.05 inch.

As a result of the at least partially curved tip 60 the taper 75 between tip 60 and base 66 of protrusion 58 over the length 72 of protrusion 58, tearing of the linerboard brought into contact with tip 60 to form a crease is substantially reduced, while forming a narrow crease width and reduced crushed region 26 (FIG. 3), thereby resulting in a reduction of unacceptable bends formed in the corrugated paperboard, and further resulting in a reduction of scrapping of manufactured corrugated paperboard, such as RSC. Stated another way, protrusion 58 is configured to form a crease, such as a main crease 78 formed in corrugated paperboard 80 in FIG. 8, the crease having sufficient depth 82 and a width 84 less than or equal to the width 68 of the base 66 of the protrusion 58 (FIG. 5), thereby resulting in a bend line formed in the corrugated paperboard that is substantially coincident with the formed crease.

As further shown in FIG. 5, length 72 of protrusion 58 is between about 0.03 inch and about 0.50 inch, between about 0.05 inch and about 0.40 inch, between about 0.07 inch and about 0.35 inch, between about 0.08 inch and about 0.30 inch, between about 0.08 inch and about 0.25 inch, between about 0.08 inch and about 0.20 inch, between about 0.08 inch and about 0.15 inch, between about 0.08 inch and about 0.10 inch, between about 0.10 inch and about 0.25 inch, between about 0.15 inch and about 0.20 inch, between about 0.20 inch and about 0.40 inch, between about 0.25 inch and about 0.35 inch, between about 0.25 inch and about 0.30 inch, or any suitable sub-range thereof. In another embodiment, protrusion 58 is about 0.25 inch.

In one embodiment, the ratio between length 72 and width 68 of base 66 of protrusion 58 is between about 0.03:1.00 and about 0.07:1.00, between about 0.07:1.00 and about 0.10:1.00, between about 0.10:1.00 and about 0.15:1.00, between about 0.15:1.00 and about 0.20:1.00, between about 0.20:1.00 and about 0.25:1.00, between about 0.25:1.00 and about 0.30:1.00, between about 0.30:1.00 and about 0.35:1.00, between about 0.35:1.00 and about 0.40:1.00, between about 0.40:1.00 and about 0.45:1.00, between about 0.45:1.00 and about 0.50:1.00, between about 0.03:0.75 and about 0.07:0.75, between about 0.07:0.75 and about 0.10:0.75, between about 0.10:0.75 and about 0.15:0.75, between about 0.15:0.75 and about 0.20:0.75, between about 0.20:0.75 and about 0.25:0.75, between about 0.25:0.75 and about 0.30:0.75, between about 0.30:0.75 and about 0.35:0.75, between about 0.35:0.75 and about 0.40:0.75, between about 0.40:0.75 and about 0.45:0.75, between about 0.45:0.75 and about 0.50:0.75, between about 0.07:0.50 and about 0.10:0.50, between about 0.10:0.50 and about 0.15:0.50, between about 0.15:0.50 and about 0.20:0.50, between about 0.20:0.50 and about 0.25:0.50, between about 0.25:0.50 and about 0.30:0.50, between about 0.30:0.50 and about 0.35:0.50, between about 0.35:0.50 and about 0.40:0.50, between about 0.40:0.50 and about 0.45:0.50, between about 0.45:0.50 and about 0.50:0.50, between about 0.07:0.40 and about 0.10:0.40, between about 0.10:0.40 and about 0.15:0.40, between about 0.15:0.40 and about 0.20:0.40, between about 0.20:0.40 and about 0.25:0.40, between about 0.25:0.40 and about 0.30:0.40, between about 0.30:0.40 and about 0.35:0.40, between about 0.35:0.40 and about 0.40:0.40, or any suitable sub-range thereof. In another embodiment, the ratio is about 0.20:0.75 inch.

As shown in FIGS. 5 and 10, circumferential portion 28 has a width 70 that is greater than the width of base 66 of protrusion 58. In another embodiment, as shown the width of circumferential portion 28 can be equal to the width of base 66 of protrusion 58.

As a result of incorporating perforating features 74 with tip 60 of protrusion 58 as previously discussed, it is now possible to provide perforated creases for different thicknesses of corrugated paperboard, as a result of adjusting the amount of compressive force applied by the tip of protrusion 58. Conventional rotary dies, while having the capability of satisfactorily simultaneously perforating and creasing a single corrugated paperboard thickness, do not have the ability to accommodate different corrugated paperboard thicknesses. That is, in response to being provided different corrugated paperboard thicknesses, conventional rotary dies cannot both satisfactorily perforate and satisfactorily crease different corrugated paperboard thicknesses.

In order to provide an extended service life, at least circumferential portion 28, including tip 60, or alternately wheel 30, circumferential portion 28, including tip 60 for a unitary construction, can be heat treated. Alternately, at least tip 60 of circumferential portion 28 can be heat treated. In one embodiment, these components can be heat treated to a Rockwell hardness number of between about 38-42, although in other embodiments, these components can be treated to a different range of Rockwell hardness numbers. It is to be understood that the circumferential portion and tip and/or wheel can be constructed of any suitable material for use in paperboard manufacturing, such as metal or metal alloy, or suitable nonmetal. The term metal is intended to include any metal alloy.

FIG. 7 is a diagrammatic view for explaining an apparatus and a method for producing an article composed of corrugated paperboard 80, such as a box in accordance with an embodiment of the present disclosure, and FIGS. 8 and 9 are enlarged front views illustrating exemplary embodiments of crease forming devices used in the apparatus according to the present disclosure. As shown in FIGS. 7 and 8-9, the apparatus for producing a corrugated paperboard box according to the present invention includes providing a feeding device (not shown) for feeding or supplying a corrugated paperboard 86. The method further includes providing a printing device (not shown) for printing 88 a predetermined pattern on the corrugated paperboard 80 which is fed by the feeding/crease forming device 90 for feeding and forming a plurality of main creases in the corrugated paperboard (“feeding/creasing 91”). Subsequent creasing (if required) and slotting devices (not shown) are provided for forming additional or supplemental creases and a plurality of slots (“subsequent creasing/slotting 92”) on the corrugated paperboard 80 which is printed with the predetermined pattern by the printing device. The method further includes providing a folding and gluing device (not shown) for folding and gluing 94 a blank composed of corrugated paperboard 80 which is formed with the main creases and the slots by the creasing and slotting device, thereby enabling the production and subsequent packing/marketing 96 of the box composed of corrugated paperboard 80.

As shown in FIG. 7, feeding/crease forming device 90 is disposed upstream of the subsequent creasing and slotting devices, for continuously forming a plurality of main creases along the same linear region on the corrugated paperboard 80 and a multi-stepwise manner such that additional and/or subsequent creases can be formed in existing main creases, if desired. That is, each supplemental crease is formed on or in-line with the last main crease of the plurality of continuously formed main creases.

As shown in FIGS. 7 and 8, feeding/crease forming device 90 comprises a plurality of main crease forming sections 98. As further shown in FIG. 8, a main crease forming section 98 is structured in a manner such that the plurality of continuously formed main creases 78 are compressively formed in the corrugated paperboard 80 as the corrugated paperboard 80 is directed or fed between at least one apparatus 110 and a support surface 100. As shown in FIG. 8, support surface 100 can be an outer surface of a wheel 102 or a corresponding apparatus 110 positioned on an opposite side of corrugated paperboard 80. FIG. 8 shows crease forming sections 98 of feeding/crease forming device 90 arranged around a pair of oppositely positioned (relative to corrugated paperboard 80) feeding shafts 104, 106 which guide feeding of the corrugated paperboard 80 using drive wheels 108. The embodiment of FIG. 9 requires only one feeding shaft 104 and drive wheels 108 secured to feeding shaft 104 to guide feeding of the corrugated paperboard 80, with an opposed support surface 100 provided to support corrugated paperboard 80 in compressive contact between opposed portions of crease forming sections 98.

While the invention has been described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims. 

What is claimed is:
 1. An apparatus for forming a bending crease in corrugated paperboard comprising: a circumferential portion of a wheel, the circumferential portion having a width and a peripheral surface positioned to compressively rollably receive a corrugated paperboard between the surface of the wheel and a support surface, the circumferential portion including a protrusion extending radially outward from the circumferential portion greater than 0.070 inch, the protrusion extending radially outward from a base to a tip opposite the peripheral surface, the tip having a width less than the width of the base; wherein the protrusion is configured to form a crease in the corrugated paperboard, the crease having sufficient depth and a width less than or equal to the width of the base, thereby resulting in a bend line formed in the corrugated paperboard that is substantially coincident with the formed crease.
 2. The apparatus of claim 1, wherein at least a portion of a profile of the tip includes a curve.
 3. The apparatus of claim 2, wherein the curve includes a radius.
 4. The apparatus of claim 1, wherein the circumferential portion is composed of a metal.
 5. The apparatus of claim 4, wherein at least the tip is heat treated.
 6. The apparatus of claim 3, wherein the radius is about 0.05 inch.
 7. The apparatus of claim 2, wherein the protrusion includes a taper between the base and the tip.
 8. The apparatus of claim 1, wherein the width of the base of the protrusion is substantially equal to or less than the width of the circumferential portion.
 9. The apparatus of claim 1, wherein the circumferential portion comprises two circumferential segments.
 10. The apparatus of claim 9, wherein the two circumferential segments include mating features formed therein.
 11. The apparatus of claim 10, wherein the mating features form a dovetail joint.
 12. The apparatus of claim 11, wherein the two circumferential segments are substantially identical to each other.
 13. The apparatus of claim 1, wherein the circumferential portion and the wheel are of unitary construction.
 14. The apparatus of claim 1, wherein the tip is configured to form a perforated crease.
 15. A system for forming a bending crease in corrugated paperboard comprising: a wheel having a circumferential portion, the circumferential portion having a width and a peripheral surface positioned to compressively rollably receive a corrugated paperboard between the surface of the wheel and a support surface, the circumferential portion including a protrusion extending radially outward from the circumferential portion greater than 0.070 inch, at least a portion of the tip the protrusion having a width less than the width of the circumferential portion; wherein the protrusion is configured to form a crease in the segment of corrugated paperboard, the crease having sufficient depth and a width less than the width of the circumferential portion, thereby resulting in a bend line formed in the segment of corrugated paperboard that is substantially coincident with the formed crease.
 16. The apparatus of claim 15, wherein at least a portion of a profile of the tip includes a curve.
 17. The apparatus of claim 16, wherein the protrusion includes a taper between the base and the tip.
 18. The apparatus of claim 15, wherein the tip is configured to form a perforated crease.
 19. A method for forming a bending crease in corrugated paperboard comprising: providing a wheel having a circumferential portion, the circumferential portion having a width and a peripheral surface positioned to compressively rollably receive a corrugated paperboard between the surface of the wheel and a support surface, the circumferential portion including a protrusion extending radially outward from the circumferential portion greater than 0.070 inch, at least a portion of the tip the protrusion having a width less than the width of the circumferential portion, the protrusion is configured to form a crease in the segment of corrugated paperboard, the crease having sufficient depth and a width less than the width of the circumferential portion, thereby resulting in a bend line formed in the segment of corrugated paperboard that is substantially coincident with the formed crease; and directing the corrugated paperboard between the protrusion and the support surface to form the crease.
 20. The method of claim 19, wherein directing the corrugated paperboard includes directing the corrugated paperboard between the protrusion and the support surface to form a perforated crease. 